The present invention is related to a process for the saccharification of celluloses, particularly to a process for the recovery of cellulases, such as hemicellulase or cellulase from the reaction mixture obtained after the degradative saccharification (hereinafter referred to as degradative saccharification liquor) of cellulosic materials with said cellulases by remarkably simple operations in high yields, and a process for the saccharification of new cellulosic materials, making use of the enzymes adhering to the solid matter which remains in the reaction mixture after the saccharification.
Saccharification of cellulosic materials has been intensively studied recently from the viewpoints of energy saving, environmental pollution, or utilization of unexploited resources, among which enzymatic saccharification is attracting public attention as an effective process, in which cellulosic materials are saccharified with simple devices and operations, under moderate conditions, without further decomposition of the produced saccharides.
In this enzymatic saccharification, the cost for the production of cellulases used as enzyme, for example cellulase or hemicellulase, is generally accepted to account for a half of the total cost. It is very important, therefore, to recover these expensive enzymes for re-utilization. A variety of methods have been suggested for the recovery of the cellulases remaining in the degradative saccharification liquor of cellulosic materials after a liquid portion is separated from the solution by centrifugation or other processes. However, there have been no suggestions at all relating to a method of recovering the cellulases which remains in the separated solid matter, and therefore cellulases have been recovered in an amount of at most 35 to 45 percent in conventional enzymatic saccharification of cellulosic materials.
Meanwhile, the present inventors have succeeded in determining the amount of the cellulases remaining in the solid matter separated from the degradative saccharification liquor of cellulosic materials using a spectropolarimeter with the finding that the amount of the cellulases remaining in this solid matter is higher than that of the cellulases remaining in the liquid portion separated from said degradative saccharification liquor, and that more than a half of the expensive cellulases have been discarded together with the solid matter in conventional enzymatic saccharification methods. It was also understood from the results of the studies of the present inventors that the activity of the cellulases remaining in said solid matter is maintained substantially completely as in the case of the cellulases remaining in said liquid portion.